1. Field of the Invention
The present invention relates to a printer driver and an image processing device, which are used in a printing machine such as a stencil printing machine, and more particular, a technique for selecting an appropriate color conversion look-up table (LUT) corresponding to ink colors used in separation printing.
2. Description of the Related Art
Polychromic printing by a multicolor printing machine such as a duotone stencil printing machine needs to carry out a so-called separation process to convert multivalued pixel values in original color spaces (e.g. a RGB color space) associated with colors of a full color original image into those in ink color spaces (e.g. a CMY color space) associated with ink colors used in multicolor printing.
There is a typical algorithm for separation printing that uses a color conversion LUT converting multivalued pixel values in the RGB color space into those in the CMY color space. The color conversion LUT is a comprehensive table including color conversion information such as color conversion, color correction/emphasis, and concentration correction. Corresponding to printing conditions such as a number of ink colors on use and their printing order, multiple kinds of color conversion LUTs are prepared. Note that the term “LUTs” means a plurality of look-up tables in this specification.
In this case, a user has to select a color conversion LUT, which is suitable for ink colors used in a multicolor printing machine and their printing order, from among the multiple kinds of color conversion LUTs. Therefore, in order to reduce a burden in the user's selecting, Japanese Patent Application Laid-Open No. 2002-86666 discloses a multicolor printing machine that detects an ink colors of printing drums by using ink-color detecting means (i.e. a combination of plural switches) and automatically performs a color conversion with reference to a ink-color combination table, based on the detected ink colors.